CI: (deps): Bump rtree from 1.3.0 to 1.4.0 in /ci

Bumps [rtree](https://github.com/Toblerity/rtree) from 1.3.0 to 1.4.0.
- [Release notes](https://github.com/Toblerity/rtree/releases)
- [Changelog](https://github.com/Toblerity/rtree/blob/main/CHANGES.rst)
- [Commits](Toblerity/rtree@1.3.0...1.4.0)

---
updated-dependencies:
- dependency-name: rtree
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

ci/doc_requirements.txt

@@ -5,4 +5,4 @@ sphinx-gallery==0.19.0
 myst-parser==4.0.1
 netCDF4==1.7.2
 geopandas==1.0.1
-rtree==1.3.0
+rtree==1.4.0